Non-invasive imaging technologies allow images of the internal structures of a patient or object to be obtained without performing an invasive procedure on the patient or object. In particular, technologies such as computed tomography (CT) use various physical principles, such as the differential transmission of x-rays through the target volume, to acquire image data and to construct tomographic images (e.g., three-dimensional representations of the interior of the human body or of other imaged structures).
A contrast agent such as iodine may be utilized to distinguish, for example, anatomical structures in a human body from surrounding soft tissue. However, the attenuation of x-rays by such contrast agents depends on the energy of the x-rays. For conventional CT imaging systems that acquire projection data at a single energy, it may be difficult to distinguish contrast-filled regions of the human body. As a result, typical approaches to enhancing contrast in such systems include an increase of contrast dosage and/or radiation dosage. Dual energy systems overcome this obstacle by acquiring projection data at a higher energy and a lower energy, where the higher energy typically corresponds to the aforementioned single energy of non-spectral CT imaging systems and the attenuation by the contrast agent is greater for photons at the lower energy. However, it remains desirable to enhance the contrast levels for non-spectral CT imaging systems without an increase of contrast dosage or radiation dosage.